Previously, the completions for `--xxx` and the corresponding
`-xxx-add` and `-xxx-rm` options were defined in separate blocks.
This caused a lot of duplicated code.
This PR removes duplication for xxx=config|group|host|placement-pref|secret.
Now the blocks for `create` and `update` only contain completions for
options that either only exist for the particular command or are specific
to it (completions for `--env-rm` and `--env|env-add` differ).
Signed-off-by: Harald Albers <github@albersweb.de>
f2b42bb6a8